certmonger: finish refactoring for request script
    
    The recent certificate refactoring assures that ipaldap operations
    are able to work with IPACertificate values when communication with
    the LDAP server. Use these capabilities and prevent possible bugs.
    
    https://pagure.io/freeipa/issue/4985
    
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>